net/mlx5e: Fix nullptr in mlx5e_tc_add_fdb_flow()
commit fe7738eb3ca3631a75844e790f6cb576c0fe7b00 upstream.
The result of __dev_get_by_index() is not checked for NULL, which then
passed to mlx5e_attach_encap() and gets dereferenced.
Also, in case of a successful lookup, the net_device reference count is
not incremented, which may result in net_device pointer becoming invalid
at any time during mlx5e_attach_encap() execution.
Fix by using dev_get_by_index(), which does proper reference counting on
the net_device pointer. Also, handle nullptr return value when mirred
device is not found.
It's safe to call dev_put() on the mirred net_device pointer, right
after mlx5e_attach_encap() call, because it's not being saved/copied
down the call chain.
Fixes: 3c37745ec6
("net/mlx5e: Properly deal with encap flows add/del under neigh update")
Addresses-Coverity: ("Dereference null return value")
Signed-off-by: Dima Chumak <dchumak@nvidia.com>
Reviewed-by: Vlad Buslov <vladbu@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Nikita Zhandarovich <n.zhandarovich@fintech.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:

committed by
Greg Kroah-Hartman

parent
8b20aab8cf
commit
40b844796b
@@ -1344,9 +1344,9 @@ mlx5e_tc_add_fdb_flow(struct mlx5e_priv *priv,
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struct netlink_ext_ack *extack)
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{
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struct mlx5_eswitch *esw = priv->mdev->priv.eswitch;
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struct net_device *out_dev, *encap_dev = NULL;
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struct mlx5e_tc_flow_parse_attr *parse_attr;
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struct mlx5_flow_attr *attr = flow->attr;
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struct net_device *encap_dev = NULL;
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struct mlx5_esw_flow_attr *esw_attr;
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struct mlx5_fc *counter = NULL;
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struct mlx5e_rep_priv *rpriv;
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@@ -1391,16 +1391,22 @@ mlx5e_tc_add_fdb_flow(struct mlx5e_priv *priv,
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esw_attr = attr->esw_attr;
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for (out_index = 0; out_index < MLX5_MAX_FLOW_FWD_VPORTS; out_index++) {
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struct net_device *out_dev;
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int mirred_ifindex;
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if (!(esw_attr->dests[out_index].flags & MLX5_ESW_DEST_ENCAP))
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continue;
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mirred_ifindex = parse_attr->mirred_ifindex[out_index];
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out_dev = __dev_get_by_index(dev_net(priv->netdev),
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mirred_ifindex);
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out_dev = dev_get_by_index(dev_net(priv->netdev), mirred_ifindex);
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if (!out_dev) {
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NL_SET_ERR_MSG_MOD(extack, "Requested mirred device not found");
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err = -ENODEV;
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return err;
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}
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err = mlx5e_attach_encap(priv, flow, out_dev, out_index,
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extack, &encap_dev, &encap_valid);
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dev_put(out_dev);
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if (err)
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return err;
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